ἥμερος, -ον/ -ως – tame, gentle, civilized; of plants: cultivated.
–> ἡμεροῦν τι/τινα – to tame, domesticate, or civilize sth/sb
τὰ ἥμερα ζῷα οὐδένα βλάπτει, ἀλλ’ ἀεὶ πράως ἔχει τε καὶ τοὺς ἀνρώπους φιλεῖ· ἥμερα δὲ ζῷά ἐστι τὰ πρόβατα, οἱ βόες, οἱ ἵπποι, αἱ αἶγες· ὁ δὲ Πλάτων (ἐν τῷ Σοφιστὴς καλουμένῳ διαλόγῳ) λέγει ὅτι ὁ μὲν κύων ἡμερώτατον ζῷόν ἐστιν, ὁ δὲ λύκος ἀγριώτατον.
Tame/domesticated animals hurt nobody but are always gentle and love the humans. Tame animals are: Sheep, cows, horses, goats. Plato says (in his dialogue „The Sophist“) that the tamest animal is the dog, the fiercest the wolf.
If you want to find out more about the mosaic you can read on here: https://museum-of-artifacts.blogspot.com/2017/01/an-egyptian-floor-mosaic-depicting-dog.html